Philadelphia could have taken its lower-salt pilot program to the city's cheesesteak shops or salty pretzel vendors. Instead, Giridhar Mallya, director of policy and planning at the Department of Health, said Philly started with Chinese food.

"We know that there are at least 400 Chinese take-out restaurants in Philadelphia, and they are predominantly in low-income, African-American and Hispanic communities," Mallya said.

Those populations have some of the highest rates -- and risks -- for high blood pressure and heart disease.

To be clear, the body needs salt. Salt's not the problem, too much salt is the problem. Scientist Gary Beauchamp says high levels of salt lurk in unexpected places -- not just potato chips -- but in bread and pasta, too.

"What happened was that salt went from something that was hard to find, very, very precious, to something that's the cheapest ingredient you can put in food with the exception of water, and even water's pretty close," said Beauchamp, director of the Monell Chemical Senses Center.

The science institute studies smell, taste and their impact on health.

Dialing back national effort in favor of local approach

Back in 2010, a national panel called on the U.S. Food and Drug Administration to force foodmakers to cut the salt. Turns out it was a radical idea, Beauchamp said, that went nowhere.

To be fair, he says, many food manufacturers are making valiant, voluntary strides to reduce sodium levels but it's tricky, he says, to tinker with beloved best-sellers such as Oreos or Big Macs.

For people who support policy change as a way to improve health, the push has largely moved to the city level.

Philadelphia is working with about 200 take-out restaurants, providing free cooking lessons and tips on adding flavor without salt. There is advice on finding suppliers that sell low-sodium ingredients at a reasonable price. The program also encourages restaurant owners to limit the number of soy sauce packets they hand to customers.

So, the next time a cashier balks when you ask for extra soy sauce, think of that denial as a good deed for your health.

Initially, a quick turnaround

Before the program began, the city analyzed the salt content in two popular takeout dishes from 20 restaurants. Months later, after the training, the secret shoppers went back. Analysts found a 20 percent reduction in sodium content.

"Frankly we were surprised the change happened so quickly," Mallya said. "Now we need to make sure it happens consistently across restaurants and consistently across their meals."

None of the restaurant owners were paid to participate in the program.

Beauchamp said there's good evidence that our taste for salt is malleable.

Studies show that abruptly starting a lower sodium diet leaves many people are unhappy with the taste of food. In six to eight weeks, people adapt, Beauchamp said.

"So things that used to taste not salty enough taste just right," he said. "And things that used to be what they liked taste too salty."

Philadelphia's Chinese take-out initiative is just one of a series of incursions on Philadelphians' salt intake. The city's menu labeling law requires chain restaurants to post sodium levels along with calorie counts.

Philadelphia has also changed the rules for its school procurement program. In order to supply the city's lunch and after-school programs, contractors have to meet the Philadelphia's salt standards.

Supporters said that focus on children could help launch a generation that consumes — and enjoys -- food with less salt.

On average, Americans gets about 3,400 mg of sodium every day. The recommendation is 2,300 mg.